To measure the scale length of a guitar, you can use a simple and effective method based on the instrument's construction.
Scale length, in the context of stringed instruments like guitars, refers to the vibrating length of the open string, from the nut to the saddle. This length is a critical factor influencing the instrument's tone, tension, and fret spacing.
The Best Way to Measure Scale Length
As recommended by experts, the best way to determine the scale length of a guitar is to measure the distance between its nut and the centre of its 12th fret. The nut is located at the headstock end of the fretboard, and the 12th fret is typically marked with double dots or another inlay pattern.
Once you've discovered the value from the nut to the 12th fret, double it. And voila – you've established the scale length.
Why Measure to the 12th Fret?
This method works because the 12th fret represents the octave point on a string. The distance from the nut to the 12th fret is theoretically exactly half the vibrating length of the open string. Doubling this measurement gives you the total scale length.
Units of Measurement
Keep in mind that guitar scale lengths are typically measured in inches. While metric measurements can also be used, inches are the standard convention in the guitar world.
Step-by-Step Measurement Guide
Here's a simple process to measure your guitar's scale length:
- Gather Your Tools: You'll need a good quality ruler or tape measure, ideally one that is rigid enough to lay flat along the fretboard. A metal ruler is often best.
- Start at the Nut: Place the end of your ruler (the zero mark) precisely at the front edge of the nut (the side closest to the headstock).
- Measure to the 12th Fret: Extend the ruler down the fretboard to the 12th fret. Note the measurement at the centre of the 12th fret wire.
- Double the Measurement: Take the measurement you recorded (from nut to 12th fret) and multiply it by two. This final number is your guitar's scale length.
Example:
If the distance from the nut to the centre of the 12th fret is exactly 12.75 inches, you would double this value:
12.75 inches * 2 = 25.5 inches
In this example, the scale length of the guitar is 25.5 inches.
Common Guitar Scale Lengths
While measurement variations can occur due to factors like fret placement or instrument setup, many guitars adhere to standard scale lengths. Knowing common lengths can help you identify your guitar's approximate scale.
| Instrument Type | Common Scale Length (Inches) |
|---|---|
| Fender Stratocaster | 25.5" |
| Gibson Les Paul | 24.75" |
| Gibson SG | 24.75" |
| Paul Reed Smith (PRS) | 25" |
| Many Acoustic Guitars | 25.4" or 25.5" |
Note: These are common examples, and variations exist.
Measuring the scale length is a fundamental step for understanding your instrument's characteristics and performing maintenance tasks like setting intonation.
